Engine control and synchronization system



Feb. 23, ,1954 J PETERSON 2,670,157

ENGINE CONTROL AND SYNCHRONIZATION SYSTEM Filed April 18, 1947 I I3 j E lo V ,l5 20 I AMPLIFIER j n F I INVENTOR.

- JUEL 0. PETERSEN BY Patented Feb. 23,1954

ENGINE CONTROL AND SYN CHRONIZATION SYSTEM Joel D. Peterson,

Bendix Aviation Ridgewood, N. 'J., assignor to Corporation,

Teterboro, N. J.,

a corporation of Delaware Application April 18, 1947, Serial No. 742,438

9 Claims.

This invention relates to an engine control and synchronization system for the automatic landing of aircraft in which signal voltages, developed by the deviation of the aircraft from the glide path beam, control the engine torque.

It has heretofore been the general practic in synchronizing the speeds of two or more engines aboard a multi-engined aircraft, to provide centrifugal means for matching the engine speed of a slave engine with that of the master engine. Such systems normally include a fly-ball governor which act upon a speeder spring for varying the propellor pitch. While such systems have proven their worth in maintaining the engine speeds synchronized during normal flight conditions, they have been found impractical in the present day practice of landing aircraft by remote control, as for example, by a system described in the copending application of Paul A.

Noxon et al. for Automatic Control of Mobile Craft bearing Serial No. 705,524 filed on October 25, 1946, now Patent No. 2,592,173.

In the landing approach system of the above disclosure, signal voltages are developed by a computer in response to the deviation of the aircraft from the localizer beam and the glide path beam broadcast from the ground station. The signal voltages thus developed are used to modify or overcome other signal voltages developed in the automatic pilot to affect the operation of rudder, elevator and aileron to maintain the craft on the two landing beams, for eventually landing the same. The airspeed of the plane may also be retarded by th developed signal voltages by reducing the speed of the engines. The reduction in engine speed in landing, however, is often such that the governing action of the prior system becomes ineffectual in that the propellor pitch is reduced to the low pitch stop. Insufficient torque is developed by the engines so that the aircraft loses headway which often results in airport crashes due to th loss of flying speed.

It is an object of my present invention to pro vide a control system for landing aircraft which is responsive to the signal voltages developed by a computer in the glide path control beam channel for reducing the engine torque.

Another object of my invention is to provide an engine control and synchronizing system for a multi-engined craft in which the speed of engine operation is controlled by beamed signal voltages and the engines synchronized to the indicated speed by a speed differential signal voltage.

A further object of this invention is to pro- 'vide a'control and synchronization system for engines which is equally operative under normal flight conditions and under landing approaches when the engine speed is materially reduced.

Yet another object of this invention is to provide a highly improved and compact engine control and synchronizing system which shall be entirely automatic in its operation, positive in its action, and relatively inexpensive to manufacture, which shall have a large variety of applications, and yet be practical and efficient to a high degree in use.

Other objects of this invention will in part be obvious, and in part hereinafter pointed out.

The invention accordingly consists in features of construction, combinations of elements, and arrangements of parts which will be exemplified in the construction hereinafter described, and of which the scope of application will be indicated in the appended claims.

In the single figure of the drawing forming a part of this specification showing a schematic wiring diagram of my novel synchronization system, l0 designates a circuit embodying one illustrative form of my present invention. The circuit I0 interconnects the controls of a master engine H and a slave engine l2 with a source of signal voltage I 3 which is connected to a computer (not shown) in the glide path control channel of a landing approach system.

The master engine H is provided with a throttle control lever l4 adapted to be moved through gearing or linkage indicated by the dotted line l5 by the rotor l6 of a two phase in duction motor 11. The motor I! is provided with a'fixed phase l8 connected to a suitable source of power l9, and a variable phase connected to the output of an amplifier 2 l.

The slave engine I2 is similarly provided with a throttle lever 22 coupled, as by 23, to the rotor 24 of a two phase motor 25. The fixed phase 25 is connected to the power sourc l9, while the variable phase 21 is connected to the output side of a second amplifier 28.

Connected across the signal source I3 is a synchronous motor or receiver having a rotor 3| coupled to the rotor It as by 32, and a stator winding 33. The rotor coil 3| is connected across the potential source I9. The stator winding 33 is connected at one end by lead 34 to on terminal of the signal source, and at the other end by lead 35 through the amplifier 2! and leads 36, 31 to the other terminal of the signal source.

The angular position of the rotor coil 3| is such that the voltage induced in the stator coil 33 of the receiver 30 balances the voltage of the signal source. No voltage will therefore be impressed on the input leads 35, 36 of the amplifier 2 I. Motor I'l will thus be at a standstill.

When a change in signal occurs, a voltage is impressed on leads 34 and 31, 36 to unbalance the circuit described, resulting in a signal being im pressed on the amplifier input leads 35, 36. This voltage is amplified Boy the amplifier 2| and applied to the'variable phase 20 of the .twoiphase motor [1. The rotor IE will thus rotate to displace angularly by way of coupling 32, the rotor coil 3i until such time when the induced voltage due to the coil 3| in the stator 'coil3'3 balances the voltage of the signal source l3. The circuit is then in equilibrium until the signal voltage [of the source I3 is again altered. 1

Rotation of the rotor I6 of the induction motor l1 will shift the throttle lever of the master engine H. The speed of the engine I'l "isthus parallel across the signal'source t3 and willactuate the respective throttle levers Mendv 22 to control the speed er :engines 1 i and Min response to the signals of the-source i 3.

Means is nowprovided' to synchronize theisp'eed ofengine 1.2 'with that of the masterengine .H.

To this end, there is provided a synchronous generator, or transmitter--50 for the master engine H. having 'a threephase :stator winding and a single phase rotor-winding 52-connected to the power source 19; and a similar transmitter 53 for the slave engine Zhavi-n'g'a threeyph'ase 1-statorwinding '5'4'andarotor winding 55. The ro- -tors' t5.2":and 55 are .adapted towbe rotated by the propellor shafts of their respective engines through the couplings indicated -:by "the dotted 'iines'i55 and '51 respectively.

.There is further provided a d-ifierential motor 1% having .a threeiphase stator zco-il'lisl and athree phase rotor coil "52.. .Thestatorcoil B1 connected byieads "63 to the-.statorcoil'tid of the slave transmitter 153, while the rotor coil 3612 'fis connectedby leads ditto the stator-coil 5-hof tlue master transmitter 50.

The rotation of the rotor coils 52and "55 "by their respective propeller shafts will induce voltages in :the stator windings 5i and 54. The voltages thus induced appear in the difierential motor windings '82 and BI, "respectively. The magnetic fields due to the currents produced thereby will rotate at a speed'proportional to th'e speed of the respective engine driving the transmitter. When thespeed'of -the rotating :fie'lds or the rotor and stator are equaltherotor G21 is at astandstill.

Should the engines "H and 12 fall out of synchronism, 'a difierenoe in the speed of the rotating fields will appear in the windings B2 andfil the interaction or" the two magneticiields resulting in theangular displacement of 'therotor winding 2. ,The angular. displacement "ofthe'rotor 62 is proportional to the. speed ldi'fierence of the two transmitter systems. I

There is now provided in the control circuit .ior the slave engine 12 a synchronous generator, transmitter- -or rotary transformer 1.0 which will 4 impress a signal voltage thereon to synchronize the speed of the slave engine with that of the master engine,

The transmitter 10 comprises a stator coil H and a rotor coil 12 connected to the potential source I9, and angularly displaceable by the rotor 32 through the coupling T3. The stator coil H is connected iin rseries into .the circuit oi the receiver '40 by leads I4 and 31.

Upon angular displacement of the differential rotor 62, the transmitter rotor 12 will be displacec'ltoin'duceasignal voltage into the circuit of the receiver 40 which is proportional to the :d-ifierence infspe'edoi the two engines. The difderentialspeednsignal voltage thus added to the :slavecontrol circuit will unbalance the circuit causing the induction motor 25 to be operated. 'Mo'tor25 will thus position the rotor 4| to rehal'anee the control circuit, at the same time moving the throttle lever 22 to reduce or increase the speed of engine 42 to bring .-the -slave engine into synchronism withthe master engine 11.

While1-have indicated the signal source .13 as lbeinga computer in the glide pathcontrol channel of -'a landing approach .system, it will be readilyapparent that the signal source I13 "could be :a transmitter of a self-synchronous system, the stator icoil being connected .to leads 34, 31 while the .rotorthereof connected to the potential source 19 being angularly *displaceable, either in response -to remote signals, or manually.

It will thus be seen that thereis provided speed .;control and synchronization system :in which the several objects of this invention "are achieved and which is well adapted to meet the conditions of practical use.

As various possible embodiments of the inventionma-y bematde, and as various chan-ges may be made in the embodiment above set forth, it is to be understood that all matter herein :set forth, or shown in the accompanying drawing, is to be interpreted as illustrative and not in a limiting :sense.

Having thus described my invention, I rel-aim .as new and desire :to secure by Letters Patent:

. 1 A synchronizing system comprising .a master engine and a slave engine, a throttle control :for each'of said-engines to vary the speed er opera- :t-ion-thereoi, an inductive transmitter for each or" said engines adapted to develop a rotating magnetic field whose (speed is proportional to theengine speed, a 'diiierential motor connected lso'said transmitters and having a rotor movable in response to :the :d-ifierence in the speed of the magnetie'fields-an inductive transmitter adapted to develop signal voltage responsive :to the angular displacement of the differential rotor, and motive means operative *by the cliiiererrtial speedsignal voltage to move the throttle-control of said slave engine to synchronize thespeeds of said'engines.

2. A -control and synchronizing :system comprising a master engine and a slave engine, means for controlling the speed oi each individual engine, asignal receiver-for :each engine, a source of signal voltage to which said receivers "are connected, means "connected to said receiver for actuating-said'control means in response-to the signal voltages of said source to vary the speed .of-sa-id engines, andmeans connected in series with the receiver of the slave engine fordeveloping a signal voltage proportional to the speed differential of said engines to synchronize the speed of the slave engine with that of the master.

:3. Asynchronizing system comprising a master engine and --a "slave engine, controlsrfor said engines to vary the rotational speed thereof; motive means for operating said controls, a source of signal voltage, a balanced circuit for each engine connected in parallel to said signal voltage source controlling said motive means, the changes in signal voltages of said source unbalancing said circuits to actuate said motive means to vary the speed of said engines, a follow-up from said motive means for balancing said circuits when engine speed is in agreement with the signal voltage, means responsive to the speed of the engines for developing signal voltages, and means in the balanced circuit for said slave engine responsive to a diiferential in speed signal voltages for unbalancing said circuit to vary the speed of the slave engine to correspond with that of the master engine.

4. A control and synchronizing system comprising a master engine, and a slav engine, controls for said engines to vary the rotational speeds thereof, a motor for moving each said controls, a source of signal voltage, a balanced circuit for controlling each of said motors connected in parallel to said signal voltage source, the changes in signal voltage unbalancing said circuits to operate said motors for varying the speed of said engines, a follow-up driven by each of said motors for balancing said motor control circuits when engine speed is in agreement with the signal voltage, a signal generator for each engine, a differential motor connected to said generators having a rotor angularly displaceable by the difference in generator signals, and means actuated by the angular displacement of the differential rotor in the control circuit of the slave motor for unbalancing said circuit to alter the speed of the slave motor to correspond with that of the master engine.

5. A control and synchronizing system comprising a master engine, and a slave engine, controls for said engines to vary the rotational speeds thereof, a motor for moving each said controls, a source of signal voltage, a balanced circuit for controlling each of said motors connected in parallel to said signal voltage source, the changes in signal voltage unbalancing said circuits to operat said motors for varying the speed of said engines, a follow-up driven by each of said motors for balancing said motor control circuits when engine speed is in agreement with the signal voltage, a signal generator for each engine, a differential motor connected to said generators having a rotor angularly displaceable by the difference in generator signals, a signal generator controlled by the angular displacement of the differential rotor to develop a signal voltage in response thereto, said signal voltag being impressed on the slave motor control circuit to alter the speed of the slave engine to correspond with that of the master engine.

6. In a landing approach system for multiengined aircraft, a throttle control for each engine of said aircraft comprising a source of signal voltage controlled by the glide path beam channel of said system, motive means for moving the throttie control of each of said engines, an inductively balanced circuit controlling each of said f e means, said circuits being connected in parallel to said signal voltage source, said circuits becoming unbalanced by changes in the signal voltages of said source to control said motive means to move the throttle controls of the engines, a signal generator driven by each engine, and inductive means responsive to the differences in generator signals to synchronize the speeds of said engines.

7. In a system of the kind described for synchronizing the speed of two engines and responsive to signals for varying engine speed, throttle mean for controlling the speed of each engine, motive means for operating each of said throttle means, an inductively balanced circuit controlling said motive means, said circuit becoming unbalanced by changes in the signals and operating said motive means, a signal generator driven by each engine, inductive means responsive to the differences in generator signals, and signal means operable by said inductive means and arranged to unbalanc said circuit and operate one of said motive means to synchronize the speeds of said engines.

8. In a synchronizing system, a master engine and a slave engine, a throttle control for each engine, an inductive transmitter driven by each of said engines, a differential motor connected to said transmitters, an inductive transmitter controlled by said diiferential motor and adapted to develop a signal voltage corresponding to the difference in speed of said engines, and motive means responsive to the signal voltage to operate said throttle control of said slave engine and synchronize the speeds of said engines.

9. In a synchronizing system, a master engine and a slave engine, a throttle control for each engine, motive means for operating each of said throttle controls, an inductively balanced circuit controlling said motive means, a signal generator driven by each engine, inductive mean responsive to the differences in generator signals, and an inductive transmitter controlled by said inductive means and arranged to unbalance said circuit and operate the motive means of said slave engine to synchronize th speeds of said engines.

JOEL D. PETERSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,971,840 Willis Aug. 28, 1934 2,223,708 Van Nes Dec. 3, 1940 2,311,642 Crane et al Feb. 23, 943 2,321,582 Crane et al June 15, 1943 2,322,225 Crane et al June 22, 1943 2,381,250 Bauman Aug. 7, 1945 2,403,243 Seppeler July 2, 1946 2,423,336 Moseley July 1, 1947 2,496,294 Kellogg Feb. 7, 1950 

